Thursday, January 29, 2009

Wings that are meant for one flight only

It happens only once during the termite year. On one warm, still summer evening, breaches appear in the towering earthen mound of an African termite nest. From the holes, fluttering a little inexpertly on gauzy wings, emerge hundreds, or sometimes thousands, of plump termites. The swarm consists of both males and females of the royal, or reproductive, caste - the only termites to grow wings. Their flight is of short duration. Though they climb some 200 ft (60 m) into the air, they travel no more than 300 yd (275 m) from their home mound. Like paratroops ridding themselves of their 'chutes, as soon as they land they termites pivot on their wings and break them off, for they are no longer needed. Both sexes search excitedly for a mate, then run off in tandem, the males hard on the females' heels. At this point they are in extreme danger, for even creatures that would not normally eat termites - spiders, shrews, lizards, birds, even local tribesmen - close in on this insect feast. Very few of the couples survive, but those that do seek a nest site in the ground or in a decaying log, and burrow in, excavating a mating chamber. It is lined with chewed wood mixed with saliva and droppings, and once it is complete, they seal themselves in.

From now on the queen, with her consort beside her, will do nothing but lay eggs, creating a colony that over years may amount to millions. Most of her offspring will become workers, sterile males and females. They forage for food - plant and wood fibres - and build and repair the nest mount, which may eventually reach a height of 30 ft (9 m).

Their taks include feeding and grooming the royal pair, as well as the soldier caste that guards the nest.


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